Field of the Invention
The present invention relates to a check valve used in a compressor.
Description of the Background Art
A variable capacity-type compressor is known. This compressor includes a check valve on a discharge passage. In the compressor including the check valve, when a high-pressure refrigerant gas is discharged from a discharge port to a discharge chamber while pushing away a discharge valve, the refrigerant gas is likely to produce pulsation. When a valve element of the check valve is pressed by the pulsating refrigerant gas, the valve element is vibrated and the noise caused by this vibration of the valve element propagates through an external refrigerant circuit to the outside, which may cause undesired sound.
Japanese Patent Laying-Open No. 2000-346217 discloses a compressor including a check valve. This check valve includes a valve housing having a communicating port. An opening area of the communicating port is less than proportional to a lift length of a valve element moving in a direction away from a valve seat. This document describes that since a large amount of a fluid in a flow path does not flow out when the lift length is small, occurrence of vibration caused by repeated opening and closing of the valve element (hunting phenomenon) is suppressed, the abnormal noise and vibration are less likely to occur, and the pressure loss can also be reduced.
When a flow rate of a refrigerant is extremely low, it becomes difficult to suppress the hunting phenomenon of the valve element. Accordingly, an object of the present invention is to provide a check valve for a compressor in which the hunting phenomenon of a valve element can be sufficiently suppressed and the operation of the valve element can be further stabilized.